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' %lnitll DAVID C. PAIGE, OF DETROIT MICHIGAN. Dcttors Patent No.87,507, dated March 2, 1869.

IMPROVEMENT IN APPARATUS FOR HARDENING-"STEEL.

The Schedule referred to in than Batters Patent and making part of thesome.

'To 'whom it may concern: 7

Be it known that 1, DAVID 0. PAIGE, of Detroit, in the county of Wayne,and State of Michigan, have invented a new and useful Improvement inHardening Steel; and I do declare that the following is a true andaccurate description thereofireference being had to the accompanyingdrawings, and to the letters of reference markedthcrcon, and being apart'of this specification.

Figure 1 is a' perspective view of my apparatus for. hardening steel.

Figure 2 is a vertical sectional view of the same upon the line X X infig. 1.

Like letters indicate like part-sin each figure.

This invention relates to hardening steel plates, .of any desired width;by placing the said plates in a suit able box or vat, so arranged that asheet of water may be inject-ed, through narrow longitudinal openings ineach side of the well, in said box or rat, within which the sheet ofsteel is placed-,heated to apropcrdegrcc, also, to plungers working inthe side chambers of said box or vat; and proper valves, by means ofwhich the sheet of water is injected; and suitable shafts, ropes, orchains, geared wheels, pinioh, and crank, by means of which the sheetsof water are injected; also, to a series of toothed racks, connectedtogether, and suspended from the top, and which are designed assupports, to hold the plates of steel in position.

A isja rectangular box or vat, composed of two watertight compartments,B, the inner longitudinal walls, 0-

G", being double, and provided with space D, extend i'ng fiom top tobottom, and the entire length of the box or vat.

There is an opening, E, at the bottom of the wall 0, leading into theadjoining compartments B, while a smaller opening, F, which iscontrolled by valves Gr, allows communication. with thecentrecompartment or well H.

A t I are longitudinal slots,' extcnding the whole length of the box,cut through the inner walls, 0

A suita le frame, J ,is suspended in the well H, and

' is provid d with a series of toothed racks, K, whose serrated edgesproject inward, and which are designed to holdthe plate of steelinposition while being subjcctcd to the water.

Each of the compartments is provided with wellfitting slides orplunger-s, L, whose bottoms are loaded,

with iron, in order to compel them to overcome the specific gravity ofthe water, 1

These plungers are raised by means of suitable ropes or chains, M, whichare secured to them, and attached to shafts N, provided with gearedwheels, which engage with the pinion O, deriving motion from the crank PThe plate of steel being heated to the proper tempcl'aturc. and insertedin the frame J, between the toothed racks K, the plungers L beingelevated, by means of the crank P, as described, and the compartments Bbeing filled with water partially, which water finds the same level inthe spaces'D, through the openingsE, Ithcn disengage the crank, allowingthe plungers to descend rapidly, thereby forcing the water to rise inthe spaces D, and injecting the same, through the longitudinal slots I,against the centre of the steelplate being operated upon, therebyhardening thei same equally.

The water, as it strikes the hot steel plate, flows upward and downwardover the surface of the plate, as

indicated by the arrows.

When the plate has been hardened, it should be withdrawn, and'the.plungers drawn up by means of the crank, as described.

The ascent of the plungers creates a. vacuum in the compartments, andthe atmospheric p1 essure drives the water out of the well. H, throughthe valves G and openings, into the said compartments, when the pressureof the water closes the valves, and retains the water in thecompartments B, when the operation described may be repeated, withanother plate of hot steel, as often as may be desircd.-

Suitable inlet pipes may be attached-to the-box or vat, to supply itwith cold water, and outlet-pipes, to

discharge the same as it becomes heated by contact with the hot plates.

By the use of the serrated edges of the holdingracks, I am able to holdthe sheet of steel straight, prevent warping, and allow of a free accessof the injected-sheet of water to the -entire length of the sheet ofsteel.

This method of hardening steel entirely does away with the difli'cultyexperienced in hardening sheets of steel by dipping them in water, whichprocess causes a warping ,of the sheets, and produces an unevenhardness.

By this process, expansion, which always takes place in hardening steel,is compelled to take place from the centre of the sheet, therebyobviating the liability to "fracture, and unequal tension upon itsvarious parts.

The necessity of forcing water against the central portions of the hotsheet of steel is to penetrate the superheated steam, which has atendency to cling to the surface of the hot steel, thereby bringing itinto close, immediate, and continued contact with the steel, at theproper'tcmperaturc.

vWhat I'olaim as my invention, and desire to secure by Letters Patent,is I 1. The hardening of sheets of steel, by forcing thin sheets of coldwater'into contact with the centre-of said sheets of steel,substantially as herein described.

2. The plungers L, operated subsmntiallyasfle scribed, in combinationwith compartments B and H, valves G, space D, and aperture I,.of vat-A,when constructed, arranged, and operated substantially as and for thepurpose set forth.

3. The frame J, providedwith serrated racks K when constructed andoperating substantially as specified, in combination with the well H,and the vat or box A, as herein described and shown. V DAVID o. PAIGE.Witnesses:

